Comment usage (Problem 2015-12-14-09-02)

Tip: It is related to the value of the javascript variable

Answer: Use the JavaScript typeof operator to find the type of current value of JavaScript variable or expression.

typeof "John" // Returns string 
typeof 3.14   // Returns number
typeof false   // Returns boolean
typeof [1,2,3,4]  // Returns object
typeof {name:'John', age:34} // Returns object

Read it for details:
JavaScript for Novices: Variables - Variables types and typeof operator 

Looking deeper: Does Java need this operator ?